矿石形状对浸堆结构及渗流场影响机制

为了研究筑堆矿石形状对堆内结构和渗流速度场分布的影响,选取了相同级配下的球团制粒矿石与普通原矿石进行柱浸实验。利用核磁共振成像(MRI)技术非接触地获取内部饱和结构,通过图像处理与统计研究了矿石形状与孔隙分布的关系,并利用Navier-Stokes方程模拟了相同压力和入渗速度下矿石形状对渗流速度场的与优势流分布影响。结果表明,饱和状态下的内部孔隙并不都服从正态分布,制粒矿石间孔隙分布更为均衡,服从正态分布,μ=2.0mm,原矿石间孔隙分布不服从正太分布,在8.00～11.00mm间缺失,最大当量直径为11.39mm;制粒矿石间速度场分布更加均匀,孔隙间无明显优势流,原矿石间速度场分布不均衡,存在贯穿结构的优势流和较大浸出盲区,出口边界表现为流场叠加状态;提出矿石形状均匀系数K可以有效描述矿石形状对内部孔隙和渗流的影响机制,K值小,孔隙分布均衡,渗流速度场分布均衡;K值大,容易产生大孔隙,连通成为优势流的通道,致使流场分布不均衡。

Effects of ore shape on pore structure and seepage velocity field in heap leaching

In order to investigate the effects of ore shapes on pore structure and seepage velocity field in heap leaching, column leaching experiments was conducted with pellet ore and crude ore in the same particle size distribution. The internal saturated structure was obtained in a non-contact way with MRI, then the relationship between ore shape and pore distribution was studied through image processing and statistics. And the Navier-Stokes equations are used to simulate the flow velocity field and the dominant flow distribution in different ore shapes under the same pressure and infiltration velocity. The results show that not all internal pores obey with normal distribution, the pore size distribution between pellet ores obey the normal distribution based on the statistical analysis, and the ; pore distribution between crude ore does not obey the normal distribution, there is a missing between.00-11.00mm, and the maximum equivalent diameter is1.39mm. In the pellet ore field the velocity distributes more evenly, and there is no obvious dominant flow; but in the crude ore field, the velocity field distribution is not balanced, and there is a distinct dominant flow and a large leaching dead zone, and the flow at the exit boundary presents coupled flow field. The effect of ore shape on the internal pores and seepage can be described by uniformity coefficient (K) effectively, the distribution of pores and seepage velocity is balanced when K value is small, when K value is large, it is easy to appear large connected pores, which is the dominant flow channel, resulting in the uneven flow field distribution.